DieselSite's Adrenaline HPOP - Big Oil

A shot of Adrenaline from DieselSite’s new HPOP

By Amy Liming, Photography by Amy Liming

8-Lug, June 01, 2011

In the world of EFI gassers, making sure your injectors can provide enough fuel to handle horsepower upgrades often requires a fuel pump upgrade, since it’s the force that pushes fuel through each orifice. In the case of our 7.3L Power Stroke project truck, Old Soldier, however, the fuel pump is plenty powerful for our plans—it’s the other pump that actually powers the injectors that needs attention.

Before we go any further, perhaps a little primer regarding exactly how 7.3L Power Strokes get fueled is in order. A standard multi-port fuel injection system, like those found on most gasser engines, relies solely on the fuel pump to ensure pressurized fuel is delivered to the injectors when the computer demands it. Diesel engines, however, run much higher compression to create combustion without an ignition system—so much higher injection pressure is required. Older diesels use a mechanical injection pump that directly actuates the injectors, but 7.3L Power Strokes do it a little differently, by utilizing a hydraulic electronic unit injection (HEUI) powered by a high-pressure oil pump (HPOP) that is geardriven off the camshaft. The fuel pump gets diesel out of the tank and into the fuel rails and injectors at around 60 to 65 psi—but that’s nowhere near what it takes. When the powertrain control module (PCM) signals for an injector to fire, the injector driver module (IDM) signals for a poppet valve inside the injector, which allows the HPOP to deliver engine oil at around 2,500 to 2,900 psi against an intensifying piston. This in turn exponentially pressurizes the diesel inside the injector to around 18,000 psi, which lifts the injector pintle from its seat and allows diesel to flow through the nozzle into the cylinder. Got all that?

The big point to take away is that most stock 7.3L HPOPs can’t maintain acceptable pressure for extended periods—even in stock form. Throw big injectors into the equation and ICP pressures can drop through the floor, resulting in poor performance, lots of smoke (the bad kind), and often a trouble code or two. But wait, you might remember that Old Solider is still running its original injectors, and we’ve got no plans to upgrade them. Big oil with stock sticks? You bet, and here’s why.

The popular opinion circulating around is that upgraded HPOPs are exclusive to the realm of trucks with larger injectors and aggressive tuning, and while it’s absolutely true that highly modified trucks will see large benefits, there’s much more to the story. Better pressures = better spray pattern = more efficient burn = more power, better fuel economy, and lower EGT. This is true no matter which level your truck is tuned to.

There are several choices on the market for wildly modified trucks requiring massive amounts of oil, but the vast majority of trucks with bolt-on parts and tuners will be more than satiated with our choice: DieselSite’s Adrenaline HPOP. Rather than big oil, think of this pump more accurately as better oil. As in, it’s designed to supply the volume and pressure that stock HPOPs should have all along while not shying away from injectors all the way up to 250cc hybrids.

Our pump wasn’t the strongest on the block, but it was certainly not to the point of causing driveability issues or increased visible smoke. To see exactly what the benefit of the Adrenaline was, we did a quick driveway swap. Tuning can mask the true benefits of any bolt-on part, so to avoid any diluting of the benefits, we’re sticking with our stone-stock tune for now for a seat-of-our-pants assessment of what the pump has to offer.

The fuel bowl needs to be removed to reach the HPOP, so to begin we drained the diesel with the yellow release valve on the backside of the bowl.

The fuel bowl needs to be removed to reach the HPOP, so to begin we drained the diesel wit

Rather than just letting it run down the valley of the engine, we installed a piece of fuel line and ran it down under the truck

Rather than just letting it run down the valley of the engine, we installed a piece of fue

There’s not much in the fuel bowl, so a small container is all that’s needed. We plan to leave the hose attached and just tuck it up by the engine cradle.

There’s not much in the fuel bowl, so a small container is all that’s needed. We plan to l

Once the bowl is empty, the hard fuel lines (arrow) can be unbolted from the base.

Our hollow, billet DieselSite CPR fuel pressure regulator replacer was removed as well so the bowl could be moved out of the way.

To remove the bowl itself, these two large bolts (arrows) on the front side of the HPOP reservoir need to be pulled. Don’t worry—they’re sealed holes. It may be necessary to remove the exhaust backpressure sensor for access.

To remove the bowl itself, these two large bolts (arrows) on the front side of the HPOP re

To avoid a big mess, the HPOP reservoir needs to be drained before removing it. The Allen wrench fill cap is the only access.

To avoid a big mess, the HPOP reservoir needs to be drained before removing it. The Allen

A fancy electric pump setup is the trick way to go, but our answer to get the oil out is to use the pump from a large bottle of Fast Orange hand cleaner. The tube is the perfect size and length—just make sure it’s clean before dropping it in.

A fancy electric pump setup is the trick way to go, but our answer to get the oil out is t

There have long been rumors that the oil in the HPOP reservoir on 7.3Ls should be changed separately, since it doesn’t circulate well and this black pool is all the proof we need. It looks (and smells) completely different from our 500-mile fresh oil in the crankcase. How old is the oil in your truck’s HPOP?

There have long been rumors that the oil in the HPOP reservoir on 7.3Ls should be changed

Once it’s been pumped dry, five 13mm bolts hold the reservoir in place.

With the reservoir now out of the way, it’s easy to reach the HPOP and fuel lines down in the engine valley.

With the reservoir now out of the way, it’s easy to reach the HPOP and fuel lines down in

To get the HPOP out, it must be disconnected from the geardrive that motivates it. This steel plate on the front of the engine behind the exhaust backpressure sensor mount is the access point.

To get the HPOP out, it must be disconnected from the geardrive that motivates it. This st

The injection control pressure sensor (ICP) provides the feedback signal for the closed-loop control of the high-pressure oil by converting pressure into a 0-5 volt signal, which the PCM uses to determine injection control pressure. Look for it on the high-pressure oil galleries on the driver-side cylinder head.

The injection control pressure sensor (ICP) provides the feedback signal for the closed-lo

Review
We can honestly say we’ve never installed any part that resulted in a more immediately noticeable change in a truck. From the moment it cranked, we could tell a difference just by the sound of the idle—it sounded smoother and somehow more powerful. That was confirmed the moment we shifted into Drive, as we could feel the engine pulling against the brakes, even though we were at idle.

Out on the road, boost levels didn’t change appreciably, but the available power certainly did. Bob Riley of DieselSite says he routinely sees 10 to 40hp gains, but the best way we know to describe the feeling is to say that it felt like our already-large 444ci big-block V-8 Power Stroke had just grown by another 100 ci. It really felt that much bigger. Going up long hills required much less additional pedal, and acceleration away from a stop was much more forceful.

Though you could feel the torque throughout the entire rpm range, the most noticeable gains were from idle to 2,000 rpm—which was ideal for around-town stop-and-go driving and towing. On top of that good news, with a sticker price of $589, DieselSite has performed what we never thought possible and kept the price of a performance HPOP within a stone’s throw of a new Ford part. Even rebuilds of stock pumps are usually in the $400 range. Honestly, it’s a no-brainer for us. Hot-rodded or stock, the Adrenaline just makes more sense.

HPOP troubleshooting tips for rough idle upon start-up after an HPOP swap:
“Most likely, you have an air bubble in the oil rails that is caught under the ICP sensor,” Bob Riley of DieselSite (www.dieselsite.com) explained. “This can be normal if you have drained your oil rails during the install by laying the oil lines down in the valley for any length of time. Some people extend the install project over several days...you will not bleed air from the rails just by running the vehicle. You must manually fill the oil that has been drained from the rails. The motor sits tilted in your truck, and the front ports are the highest point. As a result, air can easily get trapped under the ICP sensor.

“The quick fix is to remove the ICP sensor to make sure the oil rail is full and wanting to run out of the hole as you unscrew it. If it is not full, fill it up with oil using a small funnel then reinstall the sensor. Repeat this step on the passenger side with the corresponding oil rail plug on that side. Once you have removed and reinstalled both plugs and ensured both rails are full of oil, restart the truck. It should be smooth as butter now.

“If this doesn’t clear it up, you can shut the truck off and disconnect the ICP sensor. This will force the truck into a default setting (and will throw a harmless code). If the truck idles smoothly with the sensor disconnected, then your sensor is bad or there is an air bubble underneath it. If disconnecting the sensor doesn’t fix the rough idle issue, call me personally at (888) 414-3457 and we’ll run through some more complex troubleshooting with you.”

Typically, the engine’s resistance to turning will be more than enough to hold the gear still while the bolt is removed. Fortunately, it can’t fall far if you happen to drop it

Typically, the engine’s resistance to turning will be more than enough to hold the gear st

If the truck has been sitting overnight, there shouldn’t be significant fuel or pressure present in the lines, but a towel tucked underneath the lines to capture drips and some safety glasses over your eyes is always a good idea. After that, three long bolts (accessible on the backside of the HPOP) can be removed.

If the truck has been sitting overnight, there shouldn’t be significant fuel or pressure p

Side by side, it’s easy to see why the Adrenaline is a direct bolt-in with no hassle: it’s based on a stock 7.3L housing.

Side by side, it’s easy to see why the Adrenaline is a direct bolt-in with no hassle: it’s

A fully functional IPR is very important as well, since this is the sensor that will allow the pump to build pressure. There’s no reason you can’t carefully clean and reuse your stock one if it’s in good shape, but we opted for the new IPR version with our Adrenaline for a clean slate and a slim chance of outside issues affecting our test.

A fully functional IPR is very important as well, since this is the sensor that will allow

The Adrenaline also includes a new set of HPOP O-rings to provide a complete seal. We used a tiny smear of Permatex gasket maker in a couple of places to make sure they stay put while the HPOP is positioned.

The Adrenaline also includes a new set of HPOP O-rings to provide a complete seal. We used

DieselSite is kind enough to send O-rings for all line connections, and even a new grommet to seal the electrical connection.

DieselSite is kind enough to send O-rings for all line connections, and even a new grommet

It’s a good idea to properly install the O-rings on the HPOP housing right away to prevent forgetting them and creating a huge mess and a lot of backtracking. Do not transfer the original HPOP’s check valvesprings over to the Adrenaline, however.

It’s a good idea to properly install the O-rings on the HPOP housing right away to prevent

Down in the valley, the Adrenaline slides right in and installation truly is just the reverse of removal. It’s really rare when we can say that about a high-performance part.

Down in the valley, the Adrenaline slides right in and installation truly is just the reve

DieselSite includes a Ford gasket with filter for the HPOP reservoir.

With everything buttoned up, we filled the HPOP reservoir with a funnel made from a turkey baster. To completely clean out the HPOP system requires cranking and letting the truck idle for a minute or two, then shutting it down and pumping it dry again. After six cycles or so, the oil should look clean.

With everything buttoned up, we filled the HPOP reservoir with a funnel made from a turkey